Zero-point energy correction for trajectory rate data

Classical trajectory simulations are often used to calculate rate coefficients and other dynamical properties. Such calculations have a systemic error arising from leakage of zero-point energy into the reaction coordinate. Shen and Pritchard (J. Chem. Soc. Faraday Trans., 1996, 92, 4357) have recently proposed a method to correct the rate coefficient. This paper shows that the Shen-Pritchard correction factor is applicable to ergodic systems and can be derived from transition-state theory. The relationship to the quantum-mechanical threshold method of Varandas and co-workers is shown and the implications for rate and product-distribution calculations are discussed.